Neoplasia

Abdulmalik Alsheikh, MD, FRCPC

Neoplasia

• Definitions• Classification• Nomenclature• Characteristics of benign and malignant neoplasms

Neoplasia

• Cancer is one of the leading causes of death worldwide.

• Emotional and physical suffering by the patient.

• Different mortality rate …..– Some are curable – Others are fatal

Neoplasia

• Neoplasia = new growth• Neoplasm = tumor• Tumor = swelling• The study of tumors = Oncology– Oncos = tumor + ology = study of

Neoplasia

• Definition:– is an abnormal mass of tissue, – the growth of which is uncoordinated with that of normal

tissues, – and that persists in the same excessive manner after the

cessation of the stimulus which evoked the change– With the loss of responsiveness to normal growth

controls

Neoplasia

• Classification

– Benign – malignant

Neoplasia

• Benign tumors :– Will remain localized– Cannot spread to distant sites– Generally can be locally excised– Patient generally survives

Neoplasia

• Malignant neoplasms:– Can invade and destroy adjacent structure– Can spread to distant sites– Cause death (if not treated )

Neoplasia

• All tumors have two basic components:–Parechyma: made up of neoplastic cells– Stroma: made up of non-neoplastic, host-

derived connective tissue and blood vessels

Neoplasia

• The parenchyma:– Determines the biological behavior of the tumor– From which the tumor derives its name

Neoplasia

• The stroma:– Carries the blood supply– Provides support for the growth of the

parenchyma

Neoplasia

• Nomenclature– Benign tumors: • prefix + suffix• Type of cell + (-oma)

Neoplasia

• Examples:– Benign tumor arising in fibrous tissue: Fibro + oma = Fibroma

Benign tumor arising in fatty tissue: Lipo + oma = lipoma

Neoplasia

• Benign tumor arising in cartilage chondro + oma = chondroma• Benign tumor arising in smooth muscle Leiomyo + oma = leiomyoma• Benign tumor arising in skeletal muscle Rhabdomyo + oma = rhabdomyoma

Neoplasia

• epithelial benign tumors are classified on the basis of :– The cell of origin – Microscopic pattern– Macroscopic pattern

Neoplasia

– Adenoma : benign epithelial neoplasms producing gland pattern….OR … derived from glands but not necessarily exhibiting gland pattern

– Papilloma : benign epithelial neoplasms growing on any surface that produce microscopic or macroscopic finger-like pattern

Neoplasia

• Polyp : a mass that projects above a mucosal surface to form a macroscopically visible structure.

e.g. - colonic polyp - nasal polyp

Neoplasia

• Examples : – Respiratory airways: Bronchial adenoma– Renal epithelium: Renal tubular adenoma– Liver cell : Liver cell adenoma– Squamous epithelium: squamous papilloma

Neoplasia

• Malignant tumors:– Malignant tumor arising in mesenchymal tissue :

SARCOMA• From fibrous tissue: Fibrosarcoma• From bone : Osteosarcoma• From cartilage : chondrosarcoma

Neoplasia

• Malignant tumors arising from epithelial origin : CARCINOMA– Squamous cell carcinoma– Renal cell adenocarcinoma– cholangiocarcinoma

Neoplasia

• Melanoma ( skin )• Mesothelioma (mesothelium )• Seminoma ( testis )• Lymphoma ( lymphoid tissue )

See table 6 – 1 page 176 ( Robbins )

Neoplasia

• Eponymically named tumors– Hodgkin’s Lymphoma– Wilm’s Tumor ( nephroblastoma )– Burkitt’s Lymphoma

Neoplasia

Characteristics of benign and malignant neoplasms

• Differentiation and anaplasia• Rate of growth• Local invasion• metastasis

Neoplasia

1. Differentiation and anaplasia:

• Differentiation means : the extent to which the parenchymal cells of the tumor resemble their normal counterparts morphologically and functionally

Neoplasia

• well differentiated = closely resemble their normal counterparts

• Moderately differentiated• Poorly differentiated• Undifferentiated ( Anaplasia )

Neoplasia

• Benign tumors = well differentiated• Malignant tumors = well differentiated -----> anaplastic

Neoplasia

• In the histological examination of a tumor you should look for :– Pleomorphism : variation in size– High nuclear/ cytoplasm ratio ( N/C ratio)– Hyperchrmasia ( dark cell )– Mitosis ….?abnormal one

Neoplasia

Characteristics of benign and malignant neoplasms

• Differentiation and anaplasia• Rate of growth• Local invasion• metastasis

Neoplasia

• Rate of growth: – Benign tumors: • grows slowly • are affected by blood supply, hormonal effects ,

location

– Malignant tumors : • grows faster • Correlate with the level of differentiation

Neoplasia

Characteristics of benign and malignant neoplasms

• Differentiation and anaplasia• Rate of growth• Local invasion• metastasis

Neoplasia

• Local invasion :– Benign tumors : • Remain localized• Cannot invade• Usually capsulated

– Malignant tumors : • Progressive invasion• Destruction• Usually not capsulated

Neoplasia

Characteristics of benign and malignant neoplasms

• Differentiation and anaplasia• Rate of growth• Local invasion• metastasis

Neoplasia

• Metastasis : – Definition : the development of secondary

implants discontinuous with the primary tumor, possibly in remote tissues

Neoplasia

• Metastasis : – Cancers have different ability to metastasize– Approximately 30% patients present with clinically

evident metastases.– Generally, the more anaplastic and the larger the

primary tumor, the more likely is metastasis

Neoplasia

• Metastasis : three pathways – Lymphatic spread :– Hematogenous spread : – Seeding of the body cavities: pleural, peritoneal

cavities and cerebral ventricles

Neoplasia

• Lymphatic spread :– favored by carcinomas– Breasr carcinoma axillary lymph nodes– Lung carcinomas bronchial lymph nodes

Neoplasia

• Hematogenous spread : • favored by sarcomas• Also used by carcinomas• Veins are more commonly invaded• The liver and lungs are the most frequently

involved secondary sites

Neoplasia

• In the histological examination of a tumor you should look for :– Pleomorphism : variation in size– High nuclear/ cytoplasm ratio ( N/C ratio)– Hyperchrmasia ( dark cell )– Mitosis ….?abnormal one

Neoplasia

• Dysplasia : – Definiton: a loss in the uniformity of the individual

cells and a loss in their architectural orientation.– Non-neoplastic– Occurs mainly in the epithelia– Dysplastic cells shows a degree of : pleomorphism,

hyperchrmasia,increased mitosis and loss of polarity.

Neoplasia

• Dysplasia does not mean cancer• Dyplasia does not necessarily progress to

cancer• Dysplasia may be reversible• If dysplastic changes involve the entire

thickness of the epithelium it is called : CARCINOMA IN-SITU

Neoplasia

• Carcinoma in-situ– Definition: an intraepithelial malignancy in which

malignant cells involve the entire thickness of the epithelium without penetration of the basement membrane.

– Applicable only to epithelial neoplasms.

Neoplasia

• Based on the biological behavior : – Benign and malignant

• Based on the cell of origin : – One neoplastic cell type : lipoma, adenocarcinoma– More than one neoplastic cell type :

fibroadenoma– More than one neoplastic cell type derived from

more than one germ-cell layer: teratoma

Neoplasia

• Teratoma:– Teratoma contains recognizable mature or

immature cells or tissues representative of more than one germ-cell layer and some times all three.

– Teratomas originate from totipotential cells such as those normally present in the ovary and testis.

Neoplasia

• Such cells have the capacity to differentiate into any of the cell types found in the adult body. So they may give rise to neoplasms that mimic bone, epithelium, muscle, fat, nerve and other tissues.

• Most common sites are: ovary, testis

Neoplasia

• If all the components parts are well differentiated, it is a benign (mature) teratoma.

• If less well differentiated, it is an immature (malignant) teratoma.

Neplasia

• Hamartoma is apparently developmental malformation that presents as a mass of disorganized tissue indigenous to particular site. – They are distinguished from neoplasms by the fact that

they do not exhibit continued growth. they are group of tumor-like tissue masses which may be confused with neoplasms

• Choristoma– Congenital anomaly– Heterotopic rest of cells

Neoplasia

• Epidemiology– Will help to discover aetiology– Planning of preventive measures– To know what is common and what is rare.– Development of screening methods for early

diagnosis

Neoplasia

• Factors affecting incidence of cancer– Geographic and Environmental– Age– Heredity– Aquired preneoplastic disorders

Neoplasia

• Geographic and Environmental factors:– Rate of stomach carcinoma in Japan is seven times

the rate in North America and Europe.– Breast carcinoma is five times higher in North

America comparing to Japan– Liver cell carcinoma is more common in African

populations

Neoplasia

• Geographic and Environmental factors:– Asbestos : mesothelioma– Smoking : lung cancer– Multiple sexual partners: cervical cancer– Fatty diets : colonic cancer

Please see table 6-2 for occupational cancers

Neoplasia

• Factors affecting incidence of cancer– Geographic and Environmental

–Age– Heredity– Aquired preneoplastic disorders

Neoplasia

• Age:– Generally, the frequency of cancer increases with

age.– Most cancer mortality occurs between 55 and 75. – Cancer mortality is also increased during

childhood– Most common tumors of children: Leukemia,

tumors of CNS, Lymphomas, soft tissue and bone sarcomas.

Neoplasia

• Factors affecting incidence of cancer– Geographic and Environmental– Age

–Heredity– Aquired preneoplastic disorders

Neoplasia

• Heredity– Inherited Cancer Syndromes– Familial Cancers– Autosomal Recessive Syndromes of Defective DNA

repair

Heredity

• Inherited Cancer Syndromes:– Inheritance of a single mutant gene greatly

increases the risk of developing neoplasm– E.g. Retinoblastoma in children : • 40% of Retinoblastomas are familial• carriers of the gene have 10000 fold increase in the risk

of developing Retinoblastoma

– E.g. multiple endocrine neoplasia

Heredity

• Familial Cancers:– All common types of cancers occur in familial form– E.g. breast, colon, ovary,brain– Familial cancers usually have unique features:• Start at early age• Multiple or bilateral• Two or more relatives

Heredity

– Autosomal Recessive Syndromes of Defective DNA repair :• Small group of autosomal recessive disorders• Characterized by DNA instability

Please see table 6-3 for more examples

Neoplasia

• Factors affecting incidence of cancer– Geographic and Environmental– Age

–Heredity– Aquired preneoplastic disorders

Neoplasia

–Aquired preneoplastic disorders: Some Clinical conditions that predispose to cancer• Dysplastic bronchial mucosa in smokers lung

carcinoma• Atypical endometrial hypeplasia endometrial

carcinoma• Liver cirrhosis liver cell carcinoma • Margins of chronic skin fistula squamous cell

carcinoma